Lipoic acid (LA) is a sulfur containing medium chain fatty acid (C8) with a single chiral center (C6) and thus exists as two enantiomers, the naturally occurring R-(+)-lipoic acid (RLA) and S-(−)-Lipoic acid (SLA) but is generally administered as a racemic (50:50) mixture (RS-LA) for pharmaceutical and nutraceutical applications. It is an established principle of pharmacology that a single enantiomer frequently displays different pharmacodynamic (PD) profiles relative to the racemate or to its antipode. Few studies have attempted to characterize the enantioselective, non-enantioselective, quantitative and qualitative similarities and differences in the mechanisms of action between the three forms of LA, which, until clearly defined, should be considered pharmacologically distinct.
This invention, then is directed to the characterization and comparison of enantiomeric and racemic RLA and SLA as well as enantiomeric and racemic lipoamide and derivatives thereof and to pharmaceutical compositions comprising the latter, which have demonstrated surprising superior pharmacological properties and are the focus of this invention.